SIMPLE_225_TO_400_MHz_AIR_BAND_RECEIVER

Published:2009/7/17 3:06:00 Author:Jessie | From:SeekIC

Tuning coil L2 can be wound with 2 turns of #22 wire on a 5/32 drill bit. This circuit is well behaved as long as a good component layout is used. The component leads must be kept short and neat, especially the leads of the transistor. The lengths should not exceed 3/16 . Audio could be tapped off the tuning coil with a 5-μF (or so) electrolytic capacitor, but the 1N82 diode circuit seems to produce less signal loss. The, RF signal from ANT1, an approximately 18 antenna, can be introduced through a small capacitor of 1 pF (or less) to the emitter of the 2N918. Other high-frequency transistors can be used, but might require different resistance in the regeneration circuit. The output of this circuit must go to an audio amplifier.



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